This invention has to do with an improvement to the existing spool-type quick disconnect of the type positioned between a large driving shaft, as, for example, the shaft of a turbine-generator, or motor, and a driven shaft, as of a fluid drive or boiler feed pump. Conventionally, an annular bracket is bolted or otherwise secured to the end of a driving shaft. The bracket has the form of a ring with internal splines extending radially inwardly, and a co-axially extending ring of larger internal diameter, with a radially inwardly projecting lip at its end, and with no splines.
The driven shaft is also provided with an annular bracket in the form of a ring with radially inwardly extending splines, extending the full axial length of the ring. The driven shaft bracket also has a radially inwardly extending lip around an end of the bracket facing the driving shaft bracket.
A spool has flanges at both ends which are splined complementarily to the splines of the two brackets and is mounted to extend between the two brackets with the flanges of the spool engaged with the splines of the brackets in the normal, running condition. The spool has an annular channel defined by radially outwardly extending walls, in which rollers are positioned, by which the spool is shifted axially to bring the flange of the driving end of the spool into the splineless area of the driving shaft bracket, thus disconnecting the driving shaft from the driven shaft. In the conventional arrangement, there are two separate but identical roller, stub shaft, piston and double acting cylinder assemblies, located on diametrically opposite sides of the spool. In each of these assemblies, the double acting cylinders are fixedly attached to a stationary housing on opposite ends of the piston, with the central axis of the piston parallel to the central axis of the spool. Only stationary housings or cowlings have been used heretofore. One end of the stub shaft is fixedly attached to the piston; a roller is rotatably mounted on the free end of the stub shaft and is positioned between the walls defining facing sides of the annular channel around the spool. The force required to move the spool out of engagement is great, and to reduce the moment applied to the piston by the forces on the roller while moving the spool, the stub shaft is made short. Accordingly, the cylinders have been positioned closely adjacent the channel, between the facing ends of the two annular brackets.
In order to accommodate these cylinders, the shaft-to-shaft end distance has had to be on the order of forty inches, as a minimum. This not only requires that the shafts be separated by over forty inches, but has made the spool correspondingly heavy.
Both the driving shaft and the driven shaft have thrust bearings at some distance from the quick disconnect device, which fix those axial points of the shafts. Thermal growth of the turbine shaft causes that end of the assembly to expand inwardly, up to 1 1/4 inches, for example. The quick disconnect has to be so made as to accommodate this expansion.
One of the objects of this invention is to provide a quick disconnect that permits the use of a shorter spool than those used heretofore for the same application.
Another object of this invention is to provide such a quick disconnect that is capable of operation in the case of the loss of alternating current (A.C.) power.
Other objects of this invention will be apparent to those skilled in the art in light of the following description and accompanying drawings.